Ageing consists of an accumulation of changes with time both at the molecular and cellular levels, accompanying an increased susceptibility to diseases and death. If maternally inherited mitochondrial genes are involved in defining the nature and timing of ageing, and if there are genetic differences in their susceptibility to damage, a maternal contribution could be found in the inheritance of life span. The present study explores the inheritance pattern of longevity and discovers a significant genetic maternal component in human life span.